The capture and immobilization of microorganisms on a carrier is known (Patent Reference 1). The invention described in Patent Reference 1 is a method of rapidly preparing a film of microorganisms of any area and any shape on a carrier, in which the species of the microorganism forming the biofilm is controlled.
The biofilm method employed in waste water treatment is a purification method employing the pollutant decomposing action of a group of micro-organisms attaching in the form of a film to a carrier. At the start of operation of the biofilm method, it is necessary to cause the biofilm to attach to the carrier. Conventionally, however, the carrier is immersed in active sludge or a microorganism broth, and attachment of the organism requires waiting for the organism to naturally attach to the carrier. That makes it difficult to control the attachment area, attachment shape, or species of attaching microorganism. Based on the description of Patent Reference 1, the invention described in Patent Reference 1 was provided with the object of eliminating this problem.
The invention (claim 1) described in Patent Reference 1 is a method of preparing a microorganism film, characterized by: positioning in a liquid containing a microorganism a substrate on which is provided an electrode capable of generating a nonuniform electric field, applying an ac voltage to the electrode to generate a nonuniform electric field in the liquid, and rendering the permittivity of the cells of a specific microorganism greater than the permittivity of the medium to selectively cause the specific microorganism to attach to the substrate.
Attempts have been made to specify, select, and use selected cells at the single-cell level. For example, the individual detection of the antigen specificity of single lymphocytes, the retrieval of a single antigen-specific lymphocyte that has been detected, and the use of the single antigen-specific lymphocyte that has been retrieved to, for example, produce an antibody has been examined (Patent Reference 2). In Patent Reference 2, a microwell array chip is used to detect antigen-specific lymphocytes. Within the microwell array chip, the shape and dimensions of each microwell are configured so as to allow only a single lymphocyte to be contained in each microwell.
When animal cells are cultured on a substrate surface, an adhesive protein known as extracellular matrix is known to form outside the cells, attaching the cells to the substrate surface. The detachment and use of cells thus attached to the substrate surface is known. The use of an electrical stimulus as the method of detachment is known (Patent References 3 to 5).    [Patent Reference 1] Japanese Unexamined Patent Publication (KOKAI) No. 2001-161359    [Patent Reference 2] Japanese Unexamined Patent Publication (KOKAI) No. 2004-173681    [Patent Reference 3] Japanese Unexamined Patent Publication (KOKAI) No. 2008-295382    [Patent Reference 4] Japanese Unexamined Patent Publication (KOKAI) No. 2005-312343    [Patent Reference 5] Japanese Unexamined Patent Publication (KOKAI) Heisei No. 10-42857    [Nonpatent Reference 1] Manome et al., FEMS Microbiol. Lett. 197, 29-33 (2001)